drivers/s390/cio/css.c

   1 /*
   2  *  drivers/s390/cio/css.c
   3  *  driver for channel subsystem
   4  *   $Revision: 1.96 $
   5  *
   6  *    Copyright (C) 2002 IBM Deutschland Entwicklung GmbH,
   7  *                       IBM Corporation
   8  *    Author(s): Arnd Bergmann (arndb@de.ibm.com)
   9  *               Cornelia Huck (cornelia.huck@de.ibm.com)
  10  */
  11 #include <linux/module.h>
  12 #include <linux/init.h>
  13 #include <linux/device.h>
  14 #include <linux/slab.h>
  15 #include <linux/errno.h>
  16 #include <linux/list.h>
  17
  18 #include "css.h"
  19 #include "cio.h"
  20 #include "cio_debug.h"
  21 #include "ioasm.h"
  22 #include "chsc.h"
  23
  24 int need_rescan = 0;
  25 int css_init_done = 0;
  26 static int max_ssid = 0;
  27
  28 struct channel_subsystem *css[__MAX_CSSID + 1];
  29
  30 int css_characteristics_avail = 0;
  31
  32 inline int
  33 for_each_subchannel(int(*fn)(struct subchannel_id, void *), void *data)
  34 {
  35         struct subchannel_id schid;
  36         int ret;
  37
  38         init_subchannel_id(&schid);
  39         ret = -ENODEV;
  40         do {
  41                 do {
  42                         ret = fn(schid, data);
  43                         if (ret)
  44                                 break;
  45                 } while (schid.sch_no++ < __MAX_SUBCHANNEL);
  46                 schid.sch_no = 0;
  47         } while (schid.ssid++ < max_ssid);
  48         return ret;
  49 }
  50
  51 static struct subchannel *
  52 css_alloc_subchannel(struct subchannel_id schid)
  53 {
  54         struct subchannel *sch;
  55         int ret;
  56
  57         sch = kmalloc (sizeof (*sch), GFP_KERNEL | GFP_DMA);
  58         if (sch == NULL)
  59                 return ERR_PTR(-ENOMEM);
  60         ret = cio_validate_subchannel (sch, schid);
  61         if (ret < 0) {
  62                 kfree(sch);
  63                 return ERR_PTR(ret);
  64         }
  65
  66         if (sch->st != SUBCHANNEL_TYPE_IO) {
  67                 /* For now we ignore all non-io subchannels. */
  68                 kfree(sch);
  69                 return ERR_PTR(-EINVAL);
  70         }
  71
  72         /*
  73          * Set intparm to subchannel address.
  74          * This is fine even on 64bit since the subchannel is always located
  75          * under 2G.
  76          */
  77         sch->schib.pmcw.intparm = (__u32)(unsigned long)sch;
  78         ret = cio_modify(sch);
  79         if (ret) {
  80                 kfree(sch);
  81                 return ERR_PTR(ret);
  82         }
  83         return sch;
  84 }
  85
  86 static void
  87 css_free_subchannel(struct subchannel *sch)
  88 {
  89         if (sch) {
  90                 /* Reset intparm to zeroes. */
  91                 sch->schib.pmcw.intparm = 0;
  92                 cio_modify(sch);
  93                 kfree(sch);
  94         }
  95
  96 }
  97
  98 static void
  99 css_subchannel_release(struct device *dev)
 100 {
 101         struct subchannel *sch;
 102
 103         sch = to_subchannel(dev);
 104         if (!cio_is_console(sch->schid))
 105                 kfree(sch);
 106 }
 107
 108 extern int css_get_ssd_info(struct subchannel *sch);
 109
 110 static int
 111 css_register_subchannel(struct subchannel *sch)
 112 {
 113         int ret;
 114
 115         /* Initialize the subchannel structure */
 116         sch->dev.parent = &css[0]->device;
 117         sch->dev.bus = &css_bus_type;
 118         sch->dev.release = &css_subchannel_release;
 119
 120         /* make it known to the system */
 121         ret = device_register(&sch->dev);
 122         if (ret)
 123                 printk (KERN_WARNING "%s: could not register %s\n",
 124                         __func__, sch->dev.bus_id);
 125         else
 126                 css_get_ssd_info(sch);
 127         return ret;
 128 }
 129
 130 int
 131 css_probe_device(struct subchannel_id schid)
 132 {
 133         int ret;
 134         struct subchannel *sch;
 135
 136         sch = css_alloc_subchannel(schid);
 137         if (IS_ERR(sch))
 138                 return PTR_ERR(sch);
 139         ret = css_register_subchannel(sch);
 140         if (ret)
 141                 css_free_subchannel(sch);
 142         return ret;
 143 }
 144
 145 static int
 146 check_subchannel(struct device * dev, void * data)
 147 {
 148         struct subchannel *sch;
 149         struct subchannel_id *schid = data;
 150
 151         sch = to_subchannel(dev);
 152         return schid_equal(&sch->schid, schid);
 153 }
 154
 155 struct subchannel *
 156 get_subchannel_by_schid(struct subchannel_id schid)
 157 {
 158         struct device *dev;
 159
 160         dev = bus_find_device(&css_bus_type, NULL,
 161                               (void *)&schid, check_subchannel);
 162
 163         return dev ? to_subchannel(dev) : NULL;
 164 }
 165
 166
 167 static inline int
 168 css_get_subchannel_status(struct subchannel *sch, struct subchannel_id schid)
 169 {
 170         struct schib schib;
 171         int cc;
 172
 173         cc = stsch(schid, &schib);
 174         if (cc)
 175                 return CIO_GONE;
 176         if (!schib.pmcw.dnv)
 177                 return CIO_GONE;
 178         if (sch && sch->schib.pmcw.dnv &&
 179             (schib.pmcw.dev != sch->schib.pmcw.dev))
 180                 return CIO_REVALIDATE;
 181         if (sch && !sch->lpm)
 182                 return CIO_NO_PATH;
 183         return CIO_OPER;
 184 }
 185
 186 static int
 187 css_evaluate_subchannel(struct subchannel_id schid, int slow)
 188 {
 189         int event, ret, disc;
 190         struct subchannel *sch;
 191         unsigned long flags;
 192
 193         sch = get_subchannel_by_schid(schid);
 194         disc = sch ? device_is_disconnected(sch) : 0;
 195         if (disc && slow) {
 196                 if (sch)
 197                         put_device(&sch->dev);
 198                 return 0; /* Already processed. */
 199         }
 200         /*
 201          * We've got a machine check, so running I/O won't get an interrupt.
 202          * Kill any pending timers.
 203          */
 204         if (sch)
 205                 device_kill_pending_timer(sch);
 206         if (!disc && !slow) {
 207                 if (sch)
 208                         put_device(&sch->dev);
 209                 return -EAGAIN; /* Will be done on the slow path. */
 210         }
 211         event = css_get_subchannel_status(sch, schid);
 212         CIO_MSG_EVENT(4, "Evaluating schid 0.%x.%04x, event %d, %s, %s path.\n",
 213                       schid.ssid, schid.sch_no, event,
 214                       sch?(disc?"disconnected":"normal"):"unknown",
 215                       slow?"slow":"fast");
 216         switch (event) {
 217         case CIO_NO_PATH:
 218         case CIO_GONE:
 219                 if (!sch) {
 220                         /* Never used this subchannel. Ignore. */
 221                         ret = 0;
 222                         break;
 223                 }
 224                 if (disc && (event == CIO_NO_PATH)) {
 225                         /*
 226                          * Uargh, hack again. Because we don't get a machine
 227                          * check on configure on, our path bookkeeping can
 228                          * be out of date here (it's fine while we only do
 229                          * logical varying or get chsc machine checks). We
 230                          * need to force reprobing or we might miss devices
 231                          * coming operational again. It won't do harm in real
 232                          * no path situations.
 233                          */
 234                         spin_lock_irqsave(&sch->lock, flags);
 235                         device_trigger_reprobe(sch);
 236                         spin_unlock_irqrestore(&sch->lock, flags);
 237                         ret = 0;
 238                         break;
 239                 }
 240                 if (sch->driver && sch->driver->notify &&
 241                     sch->driver->notify(&sch->dev, event)) {
 242                         cio_disable_subchannel(sch);
 243                         device_set_disconnected(sch);
 244                         ret = 0;
 245                         break;
 246                 }
 247                 /*
 248                  * Unregister subchannel.
 249                  * The device will be killed automatically.
 250                  */
 251                 cio_disable_subchannel(sch);
 252                 device_unregister(&sch->dev);
 253                 /* Reset intparm to zeroes. */
 254                 sch->schib.pmcw.intparm = 0;
 255                 cio_modify(sch);
 256                 put_device(&sch->dev);
 257                 ret = 0;
 258                 break;
 259         case CIO_REVALIDATE:
 260                 /*
 261                  * Revalidation machine check. Sick.
 262                  * We don't notify the driver since we have to throw the device
 263                  * away in any case.
 264                  */
 265                 if (!disc) {
 266                         device_unregister(&sch->dev);
 267                         /* Reset intparm to zeroes. */
 268                         sch->schib.pmcw.intparm = 0;
 269                         cio_modify(sch);
 270                         put_device(&sch->dev);
 271                         ret = css_probe_device(schid);
 272                 } else {
 273                         /*
 274                          * We can't immediately deregister the disconnected
 275                          * device since it might block.
 276                          */
 277                         spin_lock_irqsave(&sch->lock, flags);
 278                         device_trigger_reprobe(sch);
 279                         spin_unlock_irqrestore(&sch->lock, flags);
 280                         ret = 0;
 281                 }
 282                 break;
 283         case CIO_OPER:
 284                 if (disc) {
 285                         spin_lock_irqsave(&sch->lock, flags);
 286                         /* Get device operational again. */
 287                         device_trigger_reprobe(sch);
 288                         spin_unlock_irqrestore(&sch->lock, flags);
 289                 }
 290                 ret = sch ? 0 : css_probe_device(schid);
 291                 break;
 292         default:
 293                 BUG();
 294                 ret = 0;
 295         }
 296         return ret;
 297 }
 298
 299 static int
 300 css_rescan_devices(struct subchannel_id schid, void *data)
 301 {
 302         return css_evaluate_subchannel(schid, 1);
 303 }
 304
 305 struct slow_subchannel {
 306         struct list_head slow_list;
 307         struct subchannel_id schid;
 308 };
 309
 310 static LIST_HEAD(slow_subchannels_head);
 311 static DEFINE_SPINLOCK(slow_subchannel_lock);
 312
 313 static void
 314 css_trigger_slow_path(void)
 315 {
 316         CIO_TRACE_EVENT(4, "slowpath");
 317
 318         if (need_rescan) {
 319                 need_rescan = 0;
 320                 for_each_subchannel(css_rescan_devices, NULL);
 321                 return;
 322         }
 323
 324         spin_lock_irq(&slow_subchannel_lock);
 325         while (!list_empty(&slow_subchannels_head)) {
 326                 struct slow_subchannel *slow_sch =
 327                         list_entry(slow_subchannels_head.next,
 328                                    struct slow_subchannel, slow_list);
 329
 330                 list_del_init(slow_subchannels_head.next);
 331                 spin_unlock_irq(&slow_subchannel_lock);
 332                 css_evaluate_subchannel(slow_sch->schid, 1);
 333                 spin_lock_irq(&slow_subchannel_lock);
 334                 kfree(slow_sch);
 335         }
 336         spin_unlock_irq(&slow_subchannel_lock);
 337 }
 338
 339 typedef void (*workfunc)(void *);
 340 DECLARE_WORK(slow_path_work, (workfunc)css_trigger_slow_path, NULL);
 341 struct workqueue_struct *slow_path_wq;
 342
 343 /*
 344  * Rescan for new devices. FIXME: This is slow.
 345  * This function is called when we have lost CRWs due to overflows and we have
 346  * to do subchannel housekeeping.
 347  */
 348 void
 349 css_reiterate_subchannels(void)
 350 {
 351         css_clear_subchannel_slow_list();
 352         need_rescan = 1;
 353 }
 354
 355 /*
 356  * Called from the machine check handler for subchannel report words.
 357  */
 358 int
 359 css_process_crw(int rsid1, int rsid2)
 360 {
 361         int ret;
 362         struct subchannel_id mchk_schid;
 363
 364         CIO_CRW_EVENT(2, "source is subchannel %04X, subsystem id %x\n",
 365                       rsid1, rsid2);
 366
 367         if (need_rescan)
 368                 /* We need to iterate all subchannels anyway. */
 369                 return -EAGAIN;
 370
 371         init_subchannel_id(&mchk_schid);
 372         mchk_schid.sch_no = rsid1;
 373         if (rsid2 != 0)
 374                 mchk_schid.ssid = (rsid2 >> 8) & 3;
 375
 376         /*
 377          * Since we are always presented with IPI in the CRW, we have to
 378          * use stsch() to find out if the subchannel in question has come
 379          * or gone.
 380          */
 381         ret = css_evaluate_subchannel(mchk_schid, 0);
 382         if (ret == -EAGAIN) {
 383                 if (css_enqueue_subchannel_slow(mchk_schid)) {
 384                         css_clear_subchannel_slow_list();
 385                         need_rescan = 1;
 386                 }
 387         }
 388         return ret;
 389 }
 390
 391 static int __init
 392 __init_channel_subsystem(struct subchannel_id schid, void *data)
 393 {
 394         struct subchannel *sch;
 395         int ret;
 396
 397         if (cio_is_console(schid))
 398                 sch = cio_get_console_subchannel();
 399         else {
 400                 sch = css_alloc_subchannel(schid);
 401                 if (IS_ERR(sch))
 402                         ret = PTR_ERR(sch);
 403                 else
 404                         ret = 0;
 405                 switch (ret) {
 406                 case 0:
 407                         break;
 408                 case -ENOMEM:
 409                         panic("Out of memory in init_channel_subsystem\n");
 410                 /* -ENXIO: no more subchannels. */
 411                 case -ENXIO:
 412                         return ret;
 413                 default:
 414                         return 0;
 415                 }
 416         }
 417         /*
 418          * We register ALL valid subchannels in ioinfo, even those
 419          * that have been present before init_channel_subsystem.
 420          * These subchannels can't have been registered yet (kmalloc
 421          * not working) so we do it now. This is true e.g. for the
 422          * console subchannel.
 423          */
 424         css_register_subchannel(sch);
 425         return 0;
 426 }
 427
 428 static void __init
 429 css_generate_pgid(struct channel_subsystem *css, u32 tod_high)
 430 {
 431         if (css_characteristics_avail && css_general_characteristics.mcss) {
 432                 css->global_pgid.pgid_high.ext_cssid.version = 0x80;
 433                 css->global_pgid.pgid_high.ext_cssid.cssid = css->cssid;
 434         } else {
 435 #ifdef CONFIG_SMP
 436                 css->global_pgid.pgid_high.cpu_addr = hard_smp_processor_id();
 437 #else
 438                 css->global_pgid.pgid_high.cpu_addr = 0;
 439 #endif
 440         }
 441         css->global_pgid.cpu_id = ((cpuid_t *) __LC_CPUID)->ident;
 442         css->global_pgid.cpu_model = ((cpuid_t *) __LC_CPUID)->machine;
 443         css->global_pgid.tod_high = tod_high;
 444
 445 }
 446
 447 static void
 448 channel_subsystem_release(struct device *dev)
 449 {
 450         struct channel_subsystem *css;
 451
 452         css = to_css(dev);
 453         kfree(css);
 454 }
 455
 456 static inline void __init
 457 setup_css(int nr)
 458 {
 459         u32 tod_high;
 460
 461         memset(css[nr], 0, sizeof(struct channel_subsystem));
 462         css[nr]->valid = 1;
 463         css[nr]->cssid = nr;
 464         sprintf(css[nr]->device.bus_id, "css%x", nr);
 465         css[nr]->device.release = channel_subsystem_release;
 466         tod_high = (u32) (get_clock() >> 32);
 467         css_generate_pgid(css[nr], tod_high);
 468 }
 469
 470 /*
 471  * Now that the driver core is running, we can setup our channel subsystem.
 472  * The struct subchannel's are created during probing (except for the
 473  * static console subchannel).
 474  */
 475 static int __init
 476 init_channel_subsystem (void)
 477 {
 478         int ret, i;
 479
 480         if (chsc_determine_css_characteristics() == 0)
 481                 css_characteristics_avail = 1;
 482
 483         if ((ret = bus_register(&css_bus_type)))
 484                 goto out;
 485
 486         /* Try to enable MSS. */
 487         ret = chsc_enable_facility(CHSC_SDA_OC_MSS);
 488         switch (ret) {
 489         case 0: /* Success. */
 490                 max_ssid = __MAX_SSID;
 491                 break;
 492         case -ENOMEM:
 493                 goto out_bus;
 494         default:
 495                 max_ssid = 0;
 496         }
 497         /* Setup css structure. */
 498         for (i = 0; i <= __MAX_CSSID; i++) {
 499                 css[i] = kmalloc(sizeof(struct channel_subsystem), GFP_KERNEL);
 500                 if (!css[i]) {
 501                         ret = -ENOMEM;
 502                         goto out_unregister;
 503                 }
 504                 setup_css(i);
 505                 ret = device_register(&css[i]->device);
 506                 if (ret)
 507                         goto out_free;
 508         }
 509         css_init_done = 1;
 510
 511         ctl_set_bit(6, 28);
 512
 513         for_each_subchannel(__init_channel_subsystem, NULL);
 514         return 0;
 515 out_free:
 516         kfree(css[i]);
 517 out_unregister:
 518         while (i > 0) {
 519                 i--;
 520                 device_unregister(&css[i]->device);
 521         }
 522 out_bus:
 523         bus_unregister(&css_bus_type);
 524 out:
 525         return ret;
 526 }
 527
 528 /*
 529  * find a driver for a subchannel. They identify by the subchannel
 530  * type with the exception that the console subchannel driver has its own
 531  * subchannel type although the device is an i/o subchannel
 532  */
 533 static int
 534 css_bus_match (struct device *dev, struct device_driver *drv)
 535 {
 536         struct subchannel *sch = container_of (dev, struct subchannel, dev);
 537         struct css_driver *driver = container_of (drv, struct css_driver, drv);
 538
 539         if (sch->st == driver->subchannel_type)
 540                 return 1;
 541
 542         return 0;
 543 }
 544
 545 static int
 546 css_probe (struct device *dev)
 547 {
 548         struct subchannel *sch;
 549
 550         sch = to_subchannel(dev);
 551         sch->driver = container_of (dev->driver, struct css_driver, drv);
 552         return (sch->driver->probe ? sch->driver->probe(sch) : 0);
 553 }
 554
 555 static int
 556 css_remove (struct device *dev)
 557 {
 558         struct subchannel *sch;
 559
 560         sch = to_subchannel(dev);
 561         return (sch->driver->remove ? sch->driver->remove(sch) : 0);
 562 }
 563
 564 static void
 565 css_shutdown (struct device *dev)
 566 {
 567         struct subchannel *sch;
 568
 569         sch = to_subchannel(dev);
 570         if (sch->driver->shutdown)
 571                 sch->driver->shutdown(sch);
 572 }
 573
 574 struct bus_type css_bus_type = {
 575         .name     = "css",
 576         .match    = css_bus_match,
 577         .probe    = css_probe,
 578         .remove   = css_remove,
 579         .shutdown = css_shutdown,
 580 };
 581
 582 subsys_initcall(init_channel_subsystem);
 583
 584 int
 585 css_enqueue_subchannel_slow(struct subchannel_id schid)
 586 {
 587         struct slow_subchannel *new_slow_sch;
 588         unsigned long flags;
 589
 590         new_slow_sch = kmalloc(sizeof(struct slow_subchannel), GFP_ATOMIC);
 591         if (!new_slow_sch)
 592                 return -ENOMEM;
 593         memset(new_slow_sch, 0, sizeof(struct slow_subchannel));
 594         new_slow_sch->schid = schid;
 595         spin_lock_irqsave(&slow_subchannel_lock, flags);
 596         list_add_tail(&new_slow_sch->slow_list, &slow_subchannels_head);
 597         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 598         return 0;
 599 }
 600
 601 void
 602 css_clear_subchannel_slow_list(void)
 603 {
 604         unsigned long flags;
 605
 606         spin_lock_irqsave(&slow_subchannel_lock, flags);
 607         while (!list_empty(&slow_subchannels_head)) {
 608                 struct slow_subchannel *slow_sch =
 609                         list_entry(slow_subchannels_head.next,
 610                                    struct slow_subchannel, slow_list);
 611
 612                 list_del_init(slow_subchannels_head.next);
 613                 kfree(slow_sch);
 614         }
 615         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 616 }
 617
 618
 619
 620 int
 621 css_slow_subchannels_exist(void)
 622 {
 623         return (!list_empty(&slow_subchannels_head));
 624 }
 625
 626 MODULE_LICENSE("GPL");
 627 EXPORT_SYMBOL(css_bus_type);
 628 EXPORT_SYMBOL_GPL(css_characteristics_avail);